Maria has been in temporary care since last week after authorities raided a Roma settlement in central Greece and later discovered that the girl was not the biological child of the Greek Roma couple she was living with. The couple were arrested and charged with abduction and document fraud.

A lawyer representing the Greek couple said they planned to seek legal custody of the fair-haired girl. The couple have told authorities they received Maria after an informal adoption.

Under Greek law, child abduction charges can include cases where a minor is voluntarily given away by the parents outside the legal adoption process.

The couple's lawyer, Costas Katsavos, said: "Now that they're in prison there's not much they can do. But provided what we said is borne out, that it was not an abduction, then logically they will be released from prison and they will be able to enter a proper [adoption] process … They truly and ardently want her back."

Costas Yannopoulos, director of the Greek children's charity Smile of the Child, which has been looking after the girl, said he had no comment on her fate. "We are dealing with the humanitarian side of this issue, looking after a young girl," Yannopoulos said.

Maria's case has drawn global attention, playing on the shocking possibility of children being stolen from their parents or sold by them. But its handling by media and authorities has raised concerns of racism toward the European Union's estimated six million Gypsies, a minority long marginalised in most of the continent.